Capillary viscometer



Oct. 12, 1937. o. FlTZ SIMONS 2,095,324

CAPILLARY VISCOMETER Filed Jan. 12, 1935 '3 Sheets-Sheet 1 FE 57.1 I /QINVENTOR ggden Fitz 527220725 ATTORN EY Oct..12, 1937. o. FlTZ SIMONS ICAPILLAR? VISCOMETER Filed Jan. 12, 1955 s neets-s'heet 2 INVENTOR OgdenFzzfzfizmons Oct: 12, 193.7.

0. FITZ S-IMONS 2,095,324 CAPILLARY VISCOMETER :3 She et s-Sheet 5 FiledJan. 12, 1935 INVENTOR BM. ATTORNEY Ogden Fitz Simona BY Patented, 1937V UNITED STATES PATENT OFFICE) Ogden Fitz Simons, Chicago, 1111,assignor to Standard Oil Company, Chicago, 111., a corporation ofIndiana Application January 12, 1935, Serial No. 1,586

6 Claims. (01. 265-11) This invention relates to improvements in Fig. isa fragmentary side elevation of the capillary viscometers and moreparticularly to viscometer of Fig. 4. viscometers employing capillariesconstructed to n the d aw I have e d r i s provide a, suspended leveltion in Fig. 1, a single tube viscometer, such as The suspended level"as employed in capilmay be used for determining the .viscosity of 5laries for various uses provides, in effect, a cirp r l u Oils andSimilar viscblls liquids The cular liquid surface that is thinner at theedges viscometer shown comprises, a single glass unit, than in themiddle, such variation and thickness with the except n of the removab estopp producing a layer of suspended liquid under the from which a.thermometer may be suspended,

1o circular surface which tends to assume the form t ou t desired, theUnit y Obviously be of a disk generated by a curved line thus t0pconstructed of separate glass elements with suitpose 'surface tensionwith the result that the able inter-oorineotine and ly m mb r surfacevis as nearly level as is possible. Greater With reference to Fig. the tumen ay accuracy is therefore afiorded by capillaries of p e all uprightCapillary 2 having a feeder the fsuspended level type because of thedybulb 3 at its upper end d ter g at its 15 namic equilibrium thusobtained which remains lower end a drop-level b illustrated nsubstantially constant over a wide viscosity t il in F A ll x n i n 5 ipr range. vided at the upper end of the bulb 3 and may I'am aware thatcapillary viscometers incorextend upwardly therefrom for a tan of oratina suspended level have heretofore approximately 3 or 4 inches- A iv lyshort 20 been used and it is, therefore, an object of my' tubular member6 in axial alignment th invention to provide certain important improve-Capillary tube. 2 Communicates at its pp end ments ther i with thebottom of the drop-level bulb 4 for a Another objecti t provide acapillary purpose hereinafter described. A liquid receivcometer, asdescribed, incorporating a novel ing bulb 7 Surrounds the tube 5 and ised 25 means for maintaining liquid to'be tested, in to provide a' liquidp oity' li h y r r than and adjacent to the capillary, at an exactprethe ag r g t C pa ty f t e d r bulb the determi d t p t therebytominimize capillary 2, the drop-level bulb 4 and the tube t i viscositydetermination 6. The bottom wall of the receiving bulb I is .Anotherobject is to provide a viscometer, as preferably located close to thelower d of the. 30

described, wherein the removal of the tested tube A filler tube 3,locatedadjacent to the liquid from the viscometer is greatlyfacilitated. Capillary 2 and P a therewith. C

A further object is to providea viscometer, rates at its lower end 9 w epper e d of as described, that will permit of the ,making of thereceiving bulb l and has its upper end ll a lurality of determinationsof the liquid to preferably level with the upper end 12 of the so betested in rapid succession and indifierent tube The diameter of e fi etube 81 pre capillaries; thereby to. facilitate the testing of erablyater t an t e diameter of the t bula liquids of unknown viscosities andto provide an members 5 and 5 so as to facilitate the flow ultimatedetermination based upon most favorqu ds t r throueh duri ad ss n and 40bl apillary size. moval of such liquids to and from the viscometer. 40

Other objects, the advantages, and uses of the uprightflushing tubeextending inventionwill become apparent. after reading lwlth the?ap1uary 2 and finel: tube commum' the following specification andclaims and after a??? g 3Y5; 533 1 52 g ggg $zfi f ip f e f fmmmg a partlevel I5 (as shown in Figure 2), formed at the w bottom of the capillaryduring the functioning magramma'tlc P of the viscometer, and. theadjacent mouth of viscometer constructed according to my lnventhe tubeThe flushing tube I3 is preferably tion; located upon that side of thecapillary 2 oppo- 2 s fragmentary Sectional Vlew 0f site to the fillertube 8 and its upper end l6 may 50 cap y tube of the instrument ofextend upwardly and level with the upper ends Fig. 3 is a view similarto Fig. 1 of a. multi- II and I2 of the filler tube 8 and tubular mem- 1capillary viscometer; her 5, respectively." I

Fig. 4 is a diagrammatic view of another form A glass vapor cell i!entirely surrounds the of the viscometer; and v assembly thus described,with the exception of 55 the uppermost ends of the filler tube 8,tubular member 5, and flushing tube l3, thereby to form a chamber withinwhich hot vapors may be confined to maintain the temperature of the viscometer and liquid therein at a predeter mined value. The lower end'ofthe cell ll terminates in a bulb l8 within which a liquid having aboiling point approximating the temperature at which the apparatus is tobe maintained is placed. Heating means, such as Bunson burner I9, may beemployed to boil the liquid within the portion l8 of the vapor cell ii.

A tubular neck 2! formed in the upper end of the cell ll and providedwith a stopper 22 affords a ready means for the introduction of athermometer 23 within the vapor cell and also facilitates the flushingand cleaning ofthe cell when required. A wire hanger 24 maybe fixed tothe stopper 22 from which the thermometer 23 may be suspended. In theinstrument illustrated the height of the cell l'l containing theviscometer proper is substantially 16 inches and the diameter of thecell approximately 2 inches.

In order to maintain the vapor within the cell H at an exactpredetermined temperature, a pressure connecting tube 25. is providedhaving one end 26 extending downwardly into the bulbular extension l8 ofthe cell to a point beneath the liquid level. The tube 25 may extendparallel with the axis of the cell I! at a distance of substantially 2inches therefrom and may be formed with a lip at its upper end, withinwhich a stopper 21 having aglass tube 28 extending therethrough isreceived. The tube 28 may be connected as by a rubber hose 29 with theintake tube 3i of a pressure control chamber 32. The chamber 32 maycomprise a glass jar closed with a stopper 33 through which extend thetube 3i and a tube 34 adapted for connection as through a tube 35' withthe intake of a suction pump (not shown). A liquid, such as mercury 36,contained within the chamber 32, provides a medium by which apredetermined pressure differential between the vapors in the cell I1and the suction pump may be maintained thereby to lower the boilingpoint of the liquid within the bulb l8 of the vapor cell so as toregulate the temperature of the vapor thus evolved by the boilingliquid. To this ,end a central glass tube 31 slidably mounted throughthe stopper 33 and submerged at its lower end within the mercury 36serves to admit only enough air to the chamber to maintain the correctpressure differential. Vertical movement of the tube 3'! operates,therefore, to attain any degree of suction within reasonable limitswithin the pressure connecting tube 25. If desired, other liquids thanmercury may be employed in the pressure control chamber 32, although Iprefer to use liquids which will not absorb condensate from any vaporswhich may enter the pressure control chamber. 2

In order to minimize the loss of vapor-producing liquid and to reducethe amount of vapors which might otherwise pass into the pressurecontrol chamber 32, I provide an air condenser 38 communicating at. 39with the upper end of the vapor cell l1 and at 4| with the lower end ofthe pressure connecting tube 25 adjacent to the portion 26 thereof. Thisarrangement results in 'the removal of non-condensible vapors from the,

25, thus to benefit by the protection of the latter members againstbreakage of the condenser and about the pressure connecting tube 25 soas to assure condensation of any vapors which might otherwise find theirway into the pressure control chamber 32. This condenser, asillustrated, may comprise an elongated condenser cell 43 surrounding themajor portion of the pressure connecting tube 25 and having an inlet 44through which cold water is admitted, an elongated tube 35 communicatingwith the upper end of the condenser cell 43 and extending downwardly andalong the axis of the tube 25, an inner water cell 46 surrounding thetube 45 and receiving water therefrom at its lower and closed end 41,and an outlet tube 48 at the upper end of the cell 46 through whichwater from the condenser is discharged. 7

The viscometer thus described comprises, in substantial unit-assembly, ahighly efficient and accurate instrument for the determination ofviscosity by observation of time and the movement of liquid to be testedwith respect to but one indicating zone defined by hair lines 5l and 52adjacent to the upper and lower ends respectively of the feeder bulb 3.

In operation the instrument is prepared for use by admitting liquid tobe tested through the open and upper end I l of the filler tube 8 in anamount sufficient to fill the receiving bulb 1. Heat from the burner [9may thereupon be applied to the liquid in the bulbular extension l8 ofthe vapor cell, ll until the thermometer 23 registers the exacttemperature at which the viscosity test is to be made. A sufiicient timeshould be allowed for the liquid within the receiving bulb l to arriveat the temperature of the vapor within the cell 11. During this phaseofoperation the tube 31 of the pressure control chamber 32 may beregulated so as to obtain the proper boiling temperature for the liquidwithin the portion 18 of the vapor cell.

It should be noted that if a suction pump is to be employed forconnection with the tube 34 of the pressure control chamber that theboiling point of the liquid placed within the vapor cell should behigher than the temperature to be maintained during the viscosity test.If desired, however, a liquid may be employed having a boiling pointwhich is lower than the required test temperature and in such case apressure pump may be substituted for the suction pump.

Subsequent to the establishment of the required operating temperaturewithin the vapor cell ll of the instrument, the liquid from thereceiving bulb I may be drawn upwardly so as to fill the drop-level bulb4, the capillary 2 and the feeder bulb 3 to a point above the level ofthe hair line 5!. This may be done by placing the finger over thenormally open end l6 of the flushing tube I3 and applying suction, asthrough a rubber hose, to the upperend H. of the tubular member 5. Thissimple procedure coupled by removing the finger from the upper end N5 ofthe flushing tube prepares the instrument for viscosity determination.Immediately upon release of the finger from the tube 13, asdescribed,-the liquid within the drop-level bulb 4 and'a small portionof the liquid which may have found its way into the prises a surfacethat is for practical. purposes without a meniscus peculiar to theviscosity of the liquid, such as that ordinarily existing at the orificeof the conventional viscometer. Upon releasing the rubber tube, appliedto the capillary extension 5, which may be held pinched together by thehand of the operator during the dropping of the surplus liquid, asdescribed, the liquid within the feeder bulb 3 will flow downwardlythrough,

the capillary and the time during which the meniscus passes between thehair lines 5| and 52 taken with the capillary diameter provides themathematical values from which the true viscosity of the liquid may becomputed. If desired, the viscosity test may be repeated withoutaltering the instrument in order to obtain an additional check upon thedetermination first made by again withdrawing a suificient amount 'ofliquid from receiving bulb 1 into the drop-level bulb, the capillary 2and the feeder bulb 3, as previously described, and thereafter releasingthe surplus liquid for time determinations in the passage of themeniscus between the hair lines 5! and 52.

After the instrument has thusbeen used and it is desired to prepare itfor other tests, the removal of all the liquid is greatly facilitated bythe simple expedient of tipping the glass unit upon its side and thuspermitting the liquid to flow out through the feeder tube 8, or byapplying suction to the upper end l2 of tube 5 and closing the upper endl6 of flushing tube l3 thereby removing substantially all of the liquidinthe receiving bulb I through the tube 6, capillary tube 2, feeder bulb3 and tube 5. As an alternative method of cleaning the apparatus suctionmay be applied to the upper end I6 of flushing tube l3, and closing theupper end l2 of tube 5. By this means the apparatus may be cleaned outwithout the necessity of dismantling the same after each determination.Flushing liquid, such as naphtha, where the liquid tested'is a petroleumproduct, may be introduced through the flushing tube It thus tothoroughly cleanse the walls of the drop-level bulb and the capillary.Such liquid may also be drawn upwardly through the capillary and blownback for complete cleansing of the capillary walls. Cleansing liquid maylikewise be removed through the filler tube 8.

In Fig. 3, I have shown another form of my improved viscometer diflering from the form illustrated in Fig. 1 only by the inclusion thereofof a plurality of capillaries (in the instrument shown I haveillustrated two capillaries) thus, improving -upon the usefulness of theinstrument for viscosity determinations with respect to liquids ofunknown viscosity. With a single tube viscometer, considerable time maybe lost in choosing one having a tube of proper capillary diameter togive accurate determination where the viscosity of the liquid beingtested is unknown to the operator. The two capillary tubes of theapparatus. of Fig. 3 differ only in diameter of the capillary bore andare represented by reference numerals corresponding to the referencenumerals of Fig. 1 with the sufiix a and b level bulb lc. In all otherrespects, the apparatus may be identical to that described in connectionwith theapparatus of Fig. 1.

In operation, the operator, after preparing the instrument to providethe required exact pre-determined temperature within the cell I! mayselect either one of the two capillaries for the first determination,using his best judgment with re- I spect to the capillary size. Shouldit be found that the time required for the movement of the meniscusbetween the hair lines at the feeder bulb is inconsistent with accurateresults he may im mediately thereafter draw the liquid into the othercapillary and repeat the test. k

While I have illustrated in Fig. 3 a viscometer containing two capillarytubes within a common vapor cell II, it should be-understood that thisnumber may be increased to as many as desired in consistency with theexpected requirements ence between the viscometer of Fig. 4 and that ofFig. 3 lies in the limitation of the so-called condenser portion 38through which non-condensible vapors may be removed from the cell I1 andwherein a measure of condensation may take place. In lieu of thisstructure I have incorporated in the device.of Fig. 4 a tube Mecomparable to the tube ll of Fig. 3 which rises upwardly within thevapor cell from the portion 260 of the pressure connecting tube 250 to apoint near the top-of the cell as indicated at 55. The upper end of thetube lie is open so that vapors may be removed from the upper portion ofthe 'cell l1 and drawn downwardly and into the pressure connecting tube25c within the water condenser cell 430. The structure of the watercondenser is modified in minor aspects by the slanting of the waterinlet and outlet tubes 44c rubber tube 290 from the pressure regulatingchamber may be connected directly to a reduced portion 28c formed at theupper end of the pressure connecting tube 250.

In order to properly accommodate the tube 4|c within the vapor cell I!in the device of Fig. 4 I have changed the positions of flushing tube l3andfiller tube 8 with respect to the capillary tubes and the drop-levelbulb 40. As indicated in Fig. 5 the filler tube' 8 joins bulb I at 90, apoint midway'between the parallel capillary tubes. The flushing tubelikewise joins the droplevel bulb 40 at a point between suspended levelsof thetube capillaries. I have also relocated the neck 2 lo throughwhich the thermometer may be inserted as indicated in Fig. 4.

In operation the device of Figs. 4 and 5 functions precisely after themanner described in connection with Fig, 3. An added advantage isattained, however, due to the elimination of the expansion coil of theso-called condenser 38, which is a relatively fragile device, and likelyto become damaged.

While I have presented herein certain embodiments of my invention bydescription and illus- 'viscometers are for the most part employed fortration of the detailed structures thereof, it is to be understood thatsuch disclosure is for the purpose of illustration only and that thescope of my invention is to be limited only by the appended claims.

I'claim:

1. A viscometer, comprising, in combination, an uprightcapillary tubeterminating at its lower end in a drop-level bulb, the bore of saidcapillary tube being fashioned, at its lower end, to effect a suspendedlevel of liquid within the bore of the tube, a feed bulb at the upperend of said capilliary tube, means facilitating quantitative measurementof liquid flowing through the tube, a vapor chamber surrounding saidtube, said feed bulb and said drop-level bulb, and having a space in itslower end for containing liquid to produce hot vapor when heated to itsboiling point, and

means for controlling the pressure in said vapor chamberto regulate atwill the boiling temperature of said vapor producing liquid.

2. A viscometer, comprising, in combination, an upright capillary tubeterminating at its lower end in a drop-level bulb, the bore of saidcapillary tubebeing fashioned at its lower end to efiect a suspendedlevel of liquid within the bore of the tube, a feed bulb at the upperend of said capillary tube, means facilitating quantitative measurementof liquid flowing through the tube, a vaporchamber surrounding saidtube, said feed bulb and said drop-level bulb, and having a space .inits lower end for containing liquid to produce hot vapor when heated toits boiling point, means for controlling the pressure in said vaporchamber to regulate at will the boiling temperature of said vaporproducing liquid, and a condenser associated with said vapor chamber forcondensing vapors from the top of said chamber and for returning thecondensate to said liquid confining space.

3. A viscometer comprising, in combination, an upright capillary tubeterminating at its lower end in a drop-level bulb, the bore of saidcapillary tube being fashioned at its lower end to effect a suspendedlevel of liquid within the bore of the tube, a feed bulb at the upperend of said capillary tube, means facilitating quantitative measurementof liquid flowing through the tube, a flushing tube connected to saiddrop-level bulb, a receiving bulb located beneath said drop-level bulbhaving a capacity greater than said capillary tube, said feed bulb andsaid drop-level bulb, a

fllling tube connected to said receiving bulb, a

vapor chamber surrounding said capillary tube, said feed bulb, saiddrop-level bulb, a major portion of said filling tube, a major portionof said flushing tube, and said receiving bulb, said vapor chamberhaving a space in its lower end for liquid to produce'hot vapor whenheated to its boiling point, means for controlling the pressure in saidvapor chamber to regulate at will the boiling temperature of said vaporproducing liquid, a condenser, said condenser associated with said vaporchamber for condensing vapors from the top of said chamber and forreturning the condensate to said liquid confining space, a secondcondensing means, said second condensing means associated with saidvapor chamber and said pressure controlling means, for condensing vaporsescaping to said controlling means and returning the condenser vapors tosaid vapor chamber.

4. A viscometer comprising, in combination, a plurality of uprightcapillary tubes of difierent capillary bores each terminating at itslower end in a common drop-level bulb, the bores of the capillary tubesbeing fashioned at their lower ends to effect a suspended level ofliquid Within the bores of the tubes, 2. feed bulb at the upper end ofeach of said capillary tubes, means facilitating quantitativemeasurement of liquid flowing through the tubes, a vapor chambersurrounding said tubes, said feed bulbs and said drop-level bulbs, andhaving a space in its lower end for containing liquid to produce hotvapor when heated to its boiling point, and means for controlling thepressure in said vapor chamber to regulate at will the boilingtemperature of said vapor producing liquid.

5. A viscometer comprising, in combination, a plurality of uprightcapillary tubes of different capillary bores each terminating at itslower end in a common drop-level bulb, the bores of the capillary tubesbeing fashioned at their lower ends to effect a suspended level ofliquid within the bores of the tubes, a feed bulb at the upper end ofeach of said capillary tubes, means facilitating quantitativemeasurement of-liquid flowing through the tubes, a vapor chambersurrounding said tubes, said feed bulbs and said droplevel bulbs, andhaving a space in its lower end for containing liquid to produce hotvapor when heated to its boiling point, and means for controlling thepressure in said vapor chamber to regulate at will the boilingtemperature of said vapor producing liquid, and a condenser associatedwith said'vapor chamber for condensing vapors from the top of saidchamber and for returning the condensate to said liquid confining space.

6. A viscometer comprising, in combination, a plurality of uprightcapillary tubes of different capillary bores each terminating at itslower end in a common drop-level bulb, the bores of the capillary tubesbeing fashioned at their lower ends to effect a suspended level ofliquid within with said vapor chamber for condensing vapors 'from thetop of said chamber and for returning the condensate to ,said liquidconfining space, a second condensing means, said second condensing meansassociated with said vapor chamber and said pressure controlling means,for condensing vapors escaping't'o said controlling means and returningthe condensed vapors to said-vapor chamber.

' OGDEN FITZ SIMONS.

